a = {1:1, 2:2}
b = {3:3, 4:4}
c = {1:10, 2:20}

#a.update(b)
a.update(c)
print a
del a[1]
print a

l1 = {1,2,3,4,5,6}
l2 = {1,2,3,4,5,6}

print dict(zip(l1,l2))
print zip(l1,l2)

a.update({})
a.update(dict(None))
